Differentiation in my local PS was a pre-test (worksheets) and if the child answered all of them correctly, then the child is given the next higher grade worksheet. There is no instruction. I am talking about math and the K/1st and 2nd grades. As for language arts, only reading is differentiated and that is done using one of the graded letters (level P, Q etc - I am not sure what the system is) - the child will be grouped into a reading group based on the level and a book will be printed off a website and the child would read it and have a discussion and answer comprehension questions. My child was in a reading group of one with the teacher as his partner because he was reading well ahead of other kids.
Still, differentiation required the parents to do all the heavy lifting where teaching was concerned because the teacher did not have the time to do the needful.
